1. Field of Invention
This invention pertains to weaving three-dimensional fabric and to a new pattern of three-dimensional fabric.
2. Description of the Prior Art
Three-dimensional fabric structures are primarily useful as the reinforcing material for a range of composite materials in which plastic resins or ceramics are used to impregnate a tailored fabric material which is then molded and cured into composite products having commercially useful physical properties tailored to acheive a desired composite application in a cost effective process.
The three basic different fabric manufacturing techniques, e.g. weaving, braiding and knitting, have all been previously used to produce three-dimensional fabric. This invention dose not pertain to braiding and knitting.
In the field of weaving, Fukuta, U.S. Pat. No. 3,834,424, disclosed the basic patent for weaving three-dimensional orthogonal fabric. The rows of yarns in the fabric produced are orthogonal at 90.degree. to each other in each of the X (warp), Y(weft), and (thickness) planes. Krauland, U.S. Pat. No. 4,526,026, and Mohamed et at, U.S. Pat. No. 5,085,252, disclose enhancements to Fukuta's method and fabric. All these machines use rapiers for weft insertion which causes them to have slow weaving speed. Further, the weaving speed is proportionally reduced as fabric width is increased. Also, practical fabric width is limited with these machines.
However, it is noted that the pattern of the fabric in these inventions appears superficially similar to this invention fabric pattern but on close examination contains several fundamental differences.
In all these machines, the fabric produced has the Z (thickness) yarns loop in the longitudinal direction (X, warp axis) over the top most Y (weft) yarn at the top. In their fabric, the Z yarns loop in the longitudinal direction (X axis) over the top most Y yarn at the top edge or under the bottom most Y yarn at the bottom edge of the fabric. Thus, the top and bottom yarns must be Y yarns and therefore there must be one more row of Y yarns than X yarns. In this invention fabric, the Z yarns loop diagonally over both an X and Y yarn at the top edge and under both an X and Y yarn at the bottom edge of the fabric at alternating angles of +45.degree. and -45.degree. to the longitudinal direction. Thus, the top most and bottom most rows of yarn may be either and X or a Y row and may be different at top from bottom. This provides the flexibility to make the number of rows of X (warp) yarns to be equal to, one more than, or one less than the number of rows of Y (weft) yarns.
In addition, the method of binding the right and left edges is different. In prior inventions, the side edges are either bound by Y yarns looped horizontally in the X direction around Z yarns or bound by independent loop stitches through the thickness of the fabric at its edges. In this invention fabric, the Z yarns bind the right most and the left most X yarns to the fabric with the +45.degree. and -45.degree. Z yarn loops at the top and bottom edges of the fabric. In addition to the above inventions in the field of weaving, Anahara et al., U.S. Pat. No. 5,137,058; Farely, U.S. Pat. No. 5,224,519 and Mohamed et al., U.S. Pat. No. 5,465,760 disclose different methods of inserting paired rows or sheets of bias yarns in the longitudinal plane between the respective rows or sheets of longitudinal yarns of a conventional woven X, Y, Z three-dimensional fabric. In all of these, the rows of Z thickness yarns loop over Y (weft) yarns the same as previously discussed for other three-dimensional fabric weaving looms. These machines also use rapiers for weft insertion and this, together with their bias yarn insertion, results in slow weaving speeds. The speeds are proportionally reduced as fabric width is increased and they are limited in the practical width of fabric they can produce.
Also in the field of weaving, Weinberg, U.S. Pat. No. 5,449,025 discloses a method of weaving X, Y, Z three-dimensional fabric utilizing a novel means for opening sheds in the Y plane for insertion of Y (weft) yarns and also in the Z plane for insertion of Z (thickness) yarns. However, this shed opening device limits the width of fabric that can be produced. Specifically, fabric widths exceeding a half meter rapidly become impractical with such a shed opening device. In addition, in the fabric produced, the Z yarns loop over the top most or bottom most Y yarns; therefore, the number of Y yarns must always be one more than the number of X yarns. Further, in the fabric produced, the method of binding the right and left side edges is to loop Y yarns over Z yarns.
Further, in the field of weaving, U.S. Pat. Nos. 4,031,922; 4,046,173; 4,066,104; 4,140,156 and 4,438,173 disclose several different methods of triaxial weaving. Triaxial woven fabric is not a true three-dimensional fabric because it is a single layer fabric, not a multilayer fabric. The fabric produced also has the major limitation that the yarns are heavily crimped and are not orthogonal to each other. This invention does not pertain to traxial weaving.
Also in the field of weaving, U.S. Pat. Nos. 3,904,464; 3,993,817; 4,001,478; and 4,080,915 discloses methods for weaving hollow cylindrical fabric structures. These machines are not capable of producing flat panels of fabric. This invention does not pertain to cylinderical weaving.